This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Reactions carried out by enzymes occur at comparatively low temperatures, usually at near-neutral pH in an aqueous environment, typically with 100% yields and 100% ee's. Enzymes almost never make undesired side products, which can be attributed to an amazing level of control over the desired reaction. This area of research asks quantitative questions about enzymes and metabolic pathways, in hopes of learning how enzymes perform difficult chemical transformations and respond to hostile environments. Enzymes that use transition metals as cofactors are of special interest. While the projects focus on enzyme mechanism and regulation in cells, experimental approaches are drawn from diverse areas of chemistry and molecular biology. The projects afford many opportunities for collaborative work.